1. Field of the Invention
The present invention relates to novel steroid hormone-antitumor derivatives and preparations thereof. More particularly, it relates to a method of modifying an antitumor drug to improve its antitumor effect and to reduce its toxicity by binding the antitumor drug to a carboxylic acid derivative of a specific steroid hormone.
2. Description of the Prior Art
When most of medicines are administrated and transferred in body organs and tissues, a ratio of the medicine transferred to the ill organs or cells is remarkably small whereas as ratio of the medicine decomposed or excreted without reaching to the ill organs or cells is remarkably large. Most of known antitumor drugs destroy tumor or cancer cells and also highly damage normal cells. Therefore, it is difficult to administrate the known antitumor drugs for a long period and it is difficult to completely destroy tumor or cancer cells.
It is remarkably effective on therapeutics, if an antitumor drug selectively affect only to tumor or cancer cells.
The inventors have studied on a method of selectively affecting a physiologically active material to the object organs or cells. As a result, it has been found that steroid hormone-antitumor derivatives obtained by binding a physiologically active material especially an antitumor drug to a steroid horomone derivative are remarkably effective for said objects.